This invention relates generally to copier apparatus, and, more particularly, to a roll fusing system for fixing electroscopic toner material to a support member.
In the process of xerography, a light image of an original to be copied is typically recorded in the form of a latent electrostatic image upon a photosensitive member with subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual image can be either fixed directly upon the photosensitive member or transferred from the member to a sheet of plain paper with subsequent affixing of the image thereto.
There are various ways of fusing or affixing the toner particles to the support member, one of which is by the employment of heat. In order to permanently affix or fuse electroscopic toner material onto a support member by heat, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This action causes the toner to be absorbed to some extent into the fibers of the support member which, in many instances, constitute plain paper. Thereafter, as the toner material cools, solidification of the toner material occurs causing the toner material to be firmly bonded to the support member. In both the xerographic as well as the electrographic recording arts, the use of thermo energy for fixing toner images onto a support member is old and well known.
One approach to thermofusing of electroscopic toner images onto a support has been to pass the support with the toner images thereon between a pair of opposed roller members, at least one of which is either externally or internally heated. During operation of a fusing system of this type, the support member to which the toner images are electrostatically adhered is moved through the nip formed between the rolls with the toner images contacting the fuser roll to thereby effect heating of the toner images within the nip.
In an arrangement of the foregoing type it is customary to apply a toner release agent is liquid form to the fuser roll structure to minimize the offsetting of toner to the fuser roll structure. Prior art constructions are known which comprise a liquid absorbing material in the form of a pad which is held in contact with the fuser roll structure. Because the pad does not contact the supply of liquid, it is necessary to provide auxilliary devices for transporting the liquid to the pad. It will be appreciated that such devices not only increase the cost of such structures but they render them more complex and sometimes create additional problems even though they may provide the solution to other problems.
The desired contact area between the pad and fuser roll structure is predetermined and the size of the pad is fabricated in accordance therewith. When the effectiveness of the pad for applying the liquid and/or cleaning toner from the fuser roll structure diminishes, it becomes necessary to replace the pad.
Accordingly, the principal object of this invention is to provide a new and improved copying apparatus.
It is a more particular object of this invention to provide a new and improved roll fusing apparatus for utilization in an electrostatic copier apparatus.
Another object of this invention is to provide a roll fusing apparatus which utilizes substantially fewer components than known roll fuser apparatus and which is therefore less costly to manufacture as well as maintain.
Yet another object of this invention is to provide new and improved applicator structure for applying toner offset preventing liquid to a heated fuser roll structure.